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[Hardware, Custom] KSP flight panel, with flight computer

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I'm using a stack of 4x7-segment LEDs connected to a custom board, driven by a multiplexed display driver. I tried the 8 digit 7 segment displays off ebay but they EAT power like it's going out of fashion. :'(

I've built a multiplexed LED driver before, with good results :)


The circuit I've cooked up for the KSP panel is extremely similar, just lighting up 8 LED's (one memory byte) at a time, and using persistence of vision to run a huge bunch of them. It runs off about 300mA, and would not really change if it was running a small number of LEDs or a full set of 128 columns.

Should be able to run 128 chars of 7-seg's worth quite nicely :)

Edited by AmeliaEatyaheart
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Nice :D

Multiplexing is the only way, really. Both in terms of hardware-requirements and power consumption. I'll personally be multiplexing my 37 7-segments in groups of ten, that should still be flicker-free without hogging the controller too much.

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Great project! I'm loving the progress you've been making. It looks like we picked out a bunch of the same hardware for our projects and ran into the same issue with the 7 segment displays from ebay.

Are the MAX7219 chips on the back of your displays becoming hot to the touch by any chance? The lot I got off of ebay turned out to have a defect in the board that shorted the 5V trace to the serial output trace and caused the chips to draw tons more power then they should have and overheat. I was able to carefully dremel out where the defect was and solder in a peice of jumper wire to get around it. Sadly I don't really have a clear picture of the fix; you can kind of see it in the fourth picture from the bottom on my DSKY album: http://imgur.com/a/6XkWy If it turns that the boards you have were manufactured with the same defect as mine I would be happy to disassemble my DSKY and take some better pictures for you.


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Are the MAX7219 chips on the back of your displays becoming hot to the touch by any chance?

Yes, very. if I keep my finger on them they can burn. Also, the serial out never worked... I wonder why ;)

Thanks for the tip! If you're able to take some photos, that would be much appreciated! thankyou! :D

(If not don't sweat, I will find this short eventually knowing what to look for :) )

If you're making something, you should show it off! Would love to see what you're making :)

Edited by AmeliaEatyaheart
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Here's a picture of the back of my 7 segment cluster. There is a single through-hole spot that was manufactured too closely to another trace. It ends up making contact and shorting out the serial out port. The first board I tried to fix was the bottom one and I messed up enough to warrent running a jumper wire. I posted my project to Reddit a couple months ago, but I'll take your advice and post it to the forum shortly.


Full Size: http://i.imgur.com/YWLv4yj.jpg

Once you make that modification the power use and heat output should plummet. It should also allow the serial output to work. Mine still flakes out every now and then after running for a while. I'm not sure if that's an issue with damage to the board, my code, or a poor solder somewhere. I'll figure it out eventually, but in the meantime the 7 segment displays look pretty cool all lit up:


I hope this helps you with your project. Good luck!

EDIT: Here's the link http://forum.kerbalspaceprogram.com/threads/101971

Edited by KK4TEE
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  • 8 months later...



So, after a huge break from this project and KSP, I've decided to get back into it and finish the flight controller :)

So, without further ado, update pix!!! :)



The controls work, though I have to re-write the code for the joysticks - I'd managed to break my deadzones. They do work though :)

The Flight computer is strictly in demo mode, I basically just need to hack the Rx line on the first arduino and cross my fingers REALLY HARD.

The square gap in the flight computer is for a 2.8" TFT screen, it was supposed to be for a virtual navball but I think it's too slow for that :( However, I can use it to draw an orbital minimap based on the orbit parameters that the plugin already spits out... :D


The fuel gauges. Dead simple to wire up, they're just 5V voltmeters, and plug straight into the PWM lines. Runs best if the arduino has external power instead of relying on USB power. :)

Still got a lot of work to do - mostly coding, with a little bit of wiring on the flight computer side.

- - - Updated - - -

Oh, and a shoutout to Sputnix for poking my brains over the last couple of weeks - they're half the reason I got back into this :)

Their KSP panel thread is here: http://forum.kerbalspaceprogram.com/threads/121245-Arduino-KSP_Serial_IO-Odysseus

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Welcome back! Your project's coming along great.

Drawing a navball on a small screen with a uC isn't impossible -

is a pretty neat demo doing it with a PIC. I'm idly considering it for 1.1 of my build, but would want to dedicate a separate controller to it. I'm not sure I'd want to put much effort in to it until the KSPSerialIO VData includes useful vectors.

Orbital minimap sounds like an awesome compromise though!

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That controller is looking AMAZING!

The green LED readouts look really great too! I went with the same... No way I was settling on red ones! :sticktongue:

The only question I have... Is there a lockout for the Oh SHI~!!! button? Cause, you know... You don't wanna accidentally Oh SH~!!! yourself! :D

Also, that's a very nice virtual navball on that video stibbons linked!

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OH MY GODS THAT IS AMAZING <3 <3 <3 <3 <3 <3


...I'm just gonna haveta give it a crack, even if it runs slow as hell.

I've got the basic code for minimap sorted, I'd be willing to share once I actually get it working, that's still a while away though :)

Yea, I did NOT want red ones for my panel. Bought a dozen, they came red anyway /rolls eyes

Managed to find replacements on ebay for the actual displays.

I'll be making a custom PCB for them eventually though, as I found those displays are rather slow :(

The OH SH!!! button has no lockout, though staging and throttle does. The throttle lockout is only in code, the stage lockout is hardwired.

It's a big button with a lot of spring to it, I don't think you can accidentally the whole thing. But if you could, it'd still be funny, cos Kerbals like blowing .... up :P

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The only question I have... Is there a lockout for the Oh SHI~!!! button? Cause, you know... You don't wanna accidentally Oh SH~!!! yourself! :D

You could always just do what they did in Apollo 13 -- just put a label over it saying "no".



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